Mendus AB presented new clinical data from the Phase 2 ADVANCE II clinical trial in acute myeloid leukemia (AML) maintenance at the European Hematology Association (EHA) 2023 Hybrid Congress. The data demonstrate that vididencel treatment led to increased levels of activated, cancer-killing T cells and reduced levels of inhibitory, immune-suppressive T cells in the majority of patients. Patients with an MRD response, the primary endpoint of the study, had the highest levels of these functional tumor antigen-specific T cells and showed a trend towards higher levels of circulating antigen-presenting cells (APCs) and B cells following vididencel treatment.

Altogether, the data provides a clear proof of the mechanism of action of Mendus' lead development program. At the time of the data cut for EHA 2023, analysis of circulating immune cells had been performed in 20 evaluable AML patients to investigate the immune system activation induced upon treatment with vididencel. Functional T-cell analysis showed vaccine induced responses (VIRs) to antigens present in vididencel in 17 out of 20 patients, with highest number of VIRs in MRD responders, providing a positive correlation of VIRs with clinical outcomes.

Analysis of individual immune cell populations showed changes in both the innate and adaptive immune cell compartments, with higher levels of tumor-reactive T cells and reduced numbers of inhibiting LAG3-expressing T-cells measured in circulation.